Known carbonylation processes, such as that disclosed in U.S. Pat. No. 3,437,676, have the drawback that relatively high pressures are necessary, while in addition the conversion rates are relatively low, which leads to long reaction times. This makes them unattractive for application on a technical scale.
European patent application No. 0106379 discloses a process for the carbonylation of propene in the presence of water or an alkanol and a catalyst, composed of palladium or a compound thereof, a triaryl phosphine and an acid as promotor. Although the reaction rate appears to be considerably increased relative to the aforementioned processes, a part of the promoter acid is lost during the course of the reaction, which results in deactivation of the catalyst system employed.
It has now been found that the reaction rate of the conversion can be maintained for a considerable time at the desired level by employing a catalyst stabilizer in catalytic quantities.